Optimization of Design Parameters of a Stirling Generator for use with a Fluidized Bed Combustor

S. Lombardi, K. Bizon, G. Continillo(Università degli Studi del Sannio), F. S. Marra (Istituto di Ricerche sulla Combustione – CNR)

This work investigates the ideal performances that could be achieved in the coupling of a Fluidized Bed Combustor with a Stirling engine by placing the head of a Stirling engine.









Feasible points (blue), in the objective space (shaft power, global efficiency) of Stirling Power and global efficiency. Red points represent the Pareto frontier of optimal solutions

The multi-objective optimization problem was solved by using the software modeFRONTIER, by employing the genetic algorithm MOGA II. The results obtained with modeFRONTIER show that the Pareto solution with the maximum efficiency presents a shaft power of about 1.75 kW with an efficiency of about 9%. However, the Pareto solution with maximum shaft power presents values of efficiency and shaft power of about 3% and 2.7 kW respectively, which are much better than the solutions obtained at the initial point.

From the results of the optimization procedure, aiming at maximizing both the mechanical power produced by the Stirling and the global efficiency, it clearly emerges that, by increasing fuel consumption, the bed temperature increases – but so do heat losses from the system, leading to an overall decrease of the effective power. The results indicate that the maximum efficiency of the system does not occur at the highest efficiency of the Stirling engine.